NEW YORK -- Right-hander Josh Johnson was forced to miss Friday night's start against the Yankees because of tightness in his right triceps.

Toronto's No. 4 starter first experienced discomfort in the area following his previous outing against New York, last Sunday. He woke up the next morning and realized something wasn't quite right.

He skipped his bullpen session later in the week with the hope that a brief period of rest would be enough to recover, but he was deemed unable to go late Thursday night.

"I've been on the other side of this before, where hopefully I'll be back in a couple of weeks or whatever, and it ends up being five months," Johnson said of the reasoning behind taking a cautious approach. "Hopefully, it won't be that. While I'm walking around and doing everything else, I don't feel it.

"When you start throwing, right when you release the ball, it feels like someone's poking you with their finger. It doesn't really hurt, but if you end up pulling a muscle back there, it can set you back a long time."

Johnson described the pain as being centered on the area where his biceps and triceps join. He's been forced to deal with a number of elbow and shoulder injuries throughout his career but said this is the first time something has popped up in this particular area.

The 29-year-old was sent for a precautionary MRI on Friday afternoon but is confident this will remain a relatively minor injury. Johnson is hopeful that he can avoid a stint on the 15-day disabled list, and intends to make his next start, which is tentatively scheduled for May 2 against Boston.

Left-hander Aaron Laffey got the call in place of Johnson. Laffey started twice for the Mets earlier this season before being claimed on waivers.

The injury couldn't have come at a worse time for the Jays. No. 1 starter R.A. Dickey is trying to battle through an injury to his upper back and neck, and the bullpen has been constantly overworked because of the lack of innings being thrown by the starters.

"It's tough no matter when it is," said Johnson, who is 0-1 with a 6.86 ERA in four starts. "You never want to miss any starts. How bad we're going right now, that's one of the [concerns], but I had pretty much everyone come up and tell me to be smart.

"[They said], 'Be smart, we want you here in September and October and not right now, not as important.' ... I'm thinking about being smart for once in my life and missing this, but I don't want it to linger on."